[rkausch]

So, my truck has been running pretty much flawlessly since I bought it in 2008. It's a 2008 SE with ~150,000 miles on it, and in the last couple of days, it's started doing a weird electrical surge kind of thing. Here's the symptoms:

• Stereo (after market Sony head unit) resets itself
• Transmission shifts into neutral
• Some of the lights on the dash light up / flash on and off really quickly
• The overdrive light turns off
• The Service Engine Soon light came on at the end of my drive into work this morning, and stayed on.

Now, not all of these things happen all the time, but the Stereo resetting itself seems to happen in all cases, and the transmission thing seems to happen in about 80% of the cases. The dash lights happen less frequently. The engine never quits though, while it's in neutral, I can rev the engine, and the RPM gauge reflects accurately (I think) the state of the engine.

I drive about 40 miles each way to work (almost all highway), and this morning, everything was fine until about mile 30, at which point I climb about a 5% grade hill for about a mile or so, putting the engine under a little more load than standard driving. It cut out / went to neutral as described above about 6 times in 5 minutes, and I almost didn't make it up the hill.

Things that I have changed / messed with recently in the truck:

1. Brake Job - about 2 weeks ago, full replacement of all rotors and pads, including parking brake pads
2. Trailer Hitch and Electrical Package with 4 wire harness - about 2 months ago
3. New Sony Head Unit - about 2.5 years ago (I pulled it out and ripped out a previously installed Satellite Radio receiver that I was no longer using about a month ago)

Anyway, I've been racking my brain trying to think through what may be causing this. I usually point to things that I've done as the first culprit, but the brake job probably doesn't have anything to do with electrical issues. The trailer hitch and electrical harness have been on about 2 months, and has been used once without issue, and the head unit has been in there long enough that it would have caused problems a long time ago (I'm guessing).

That leaves other potential issues: Alternator going out, Distributor going out, others?

Anyway, thank you in advance for any insight!

 

[rkausch]

So, I feel like a complete idiot, but I have identified and fixed the issue. Turns out the battery hold-down had come loose and was arcing intermittently on the negative battery terminal. Fixed that, and everything runs great again!

So, the only remaining issue is that the "Service Engine Soon" light is still on. I think that's different than the Check Engine Light, but is an error code responsible for turning that light on too? How do I read that / reset it?

 

[AndysLog]

shouldnt be arking off the negative.
you have issues if it is, or it was the positive.

 

[geekmyride]

If the hold down was loose, there is a good chance the battery was bouncing around and the battery terminals are now loose as well. Would check them for corrosion and that the connections are tight....

 

[rkausch]

I double checked, and it was indeed the positive terminal. My bad. I'll definitely check the the terminals and make sure they're tight. I didn't have any corrosion on them though, which is good.